Core drill plug



Aug. 18, 1931. F. SCOTT CORE DRILL PLUG Filed Oct. 27. 1950 Big. 2

' Gimp 00.50003 INYENTOR V ATTORNEY Patented Aug. 18,1931

UNITED, STATES PAT NT- OFFICE FLOYD L. SCOTT, F HOUSTON, TEXAS, ASSIGNOR' TO HUGHES TOOL COMPANY, OI

. HOUSTON, TEXAS, A CORPORATION OF TEXAS CORE DRILL PLUG Application filed October 27,1930. Serial No. 491,476.

My invention relates to plugs for closing the lower end of the core barrel when the core drill is being introduced into the hole. Plu s' of this general character have been emp oyed before. The plug is commonly secured in the drill or core barrelby releasable means such as a threaded connection where disconnection is accomplished by rotation of the drill upon the bottom; or the plug may be held in place by a frangible pin which is sheared off to release the plug when. the plug engagesthe well bottom.

There are. objections to both these prior means of holding the plug in position. The

16 bit may encounter bridges of earth and rock necessitating rotation of the drill to break through the bridge and thus the threaded plug may unscrew before the bottom is reached. With the frangible pin, the striking of a blow upon the lug by encountering a rock or other obstac e may rupture the connection andrelease the plug prematurely.

It is an object of my invention to provide a plug and means to retain it in position until it is desirable to release it at the bottom of the well. I provide a holding means that can peated operations, and which will last forng periods of time.

In the drawmgs herewith, Fig. 1 is a cen- 'tral vertical section through a core drill and core barrel with my invention employedthereon. Fig. 2 is a similar view showing the plug in released position."

. My plug may be used with any ordinary type 0 core drill. 1 have illustrateda scraping core bit of common construction having a head 1 with a threaded socket 2 thereon to receive the threaded pin 3 upon the drill collar or barrel 4. The drill has a pluralit of outwardly extending blades 5 which may 1i ve a hard facing thereon indicated at 6. he head is tubularand has an inner upwardly- 6 presented shoulder 7 upon which the plug'A -ly to form a shoulder 12 to seat upon the .has a nut 19 thereon to hold said may be supported. Flushing fluid for the drill is conducted to the forward sides of the blades through passages 8 in the collar connecting with an annular channel 9 in the drill head. Discharge ports 10 in the head are formed to connect with the channel 9.

The plug A comprises a cylindrical body 11 which is preferably hollow. Its up er portion has its outer diameter increa slightshoulder 7 in the bit. The upper extremity of the plug is tapered to a reduced portion 13 through which a bolt orpin 14 may pass. Said pin 14 has a lower head 15 closing the lower end of the plug. The pinhas an elon-' gated neck 16 with a shoulder at the upper end of the same to form a seat for a ring 17 of soft material such as lead. Said ring is beveled from its ends toward the middle to provide a sharp edge to bear against the pivoted dog 18. The upper end of the pin 14 pin assembled in the plug. K I have shown one dog 18 pivoted at its upper end to lugs 20, but it is to be understood that several such dogs may be used. Said dog is an elongated blade pivotally supported upon a pin 21 supported in the lugs 20, and depending downwardly into a slot 22 in the side wall of the plug. The inner side of the dog bears-against the ring 17 The outer side projectsslightly from the plug and has a beveled notch or recess 23 formed therein to regeitl'le the lower shouldered portion 7 of the By reference toFig. 1 it will be seen that when the dog engages the ring 17, the blade willbe held outwardly to latch the plug in position, the movement of the plug being limited by the length of the notch 23. The upper end of the pin may have a sleeve 25 thereon to limit the inward movement of the dimg when it has been depressed to release the ug. 1 p When the drill is goin into the hole the accidental engagement of the plug wit an obstruction may serve to indent the soft metal ring 17 slightly but not sufliciently to release the plug. The action of the pumps will flush by rotating the same to a new the bitand finally indent the dog into the ring as shown in Fig. 2 sufliciently to force the dog past the shouldered end 7 of the bit and allow the plu to move upwardly ahead of the core forme by the drill in the subsequent drilling operations.

v The advantage of the plug thus formed lies in the fact that the same is not easily released through accidental blows thereon. The lead ring is crushed only by repeated heavy blows such as may be ex erienced by contact with the well bottom. urther, the plug may be easily repaired for subsequent use by wlthdrawing the pin 14, removing the ring'17 and substituting a new one. in fact, the same ring may be employed a second time position on the pin relative to the dog or dogs.

What I claim as new is: 1. A core drillhaving a central core passage therethrough, a shoulder on the inner wall of said passage, a plug in said passage,

a late-rally projecting pivoted dog on said plug having a beveled notch therein to receive said shoulder, and means holding said dog extended to engage said notch with said shoulder compressible by repeated blows to allow said dog to be disengaged from said shoulder.

2. A core drill having a central core passage therethrough, a shoulder on the inner wall of said passage, a plug in said passage, a laterally rejecting pivoted dog on said plu having a eveled notch therein to receive sai shoulder, and means insaid plug positioned to bear against said dog to h d it in en agement with said shoulder, said means ing compressible under high pressure to allow said dog to move inwardly and be released from said shoulder.

3. A core drill havin a central core passage therethrough, a p u in said passage latching means on said p ug engaglng said drill to latch said lug insaid passage, and means engagingsaid latching means to hold it in operative position compressible under strain to release said latching means.

4. A core drill having a central core passage therethrough, a plug in said passage, latching means on said plug engaging in said passage to limit longitudinal movement of said plug, and means to hold said latching means in drill-engaging position compress- -ible under shock to release said latching means and said plug.

5. A core drill having a core passage therethrough, a plug in said assage, and means holding sai plug in sai passage compressible to release said plug under longitudinal strain upon said plug.

6. A core drill, a plug closing the core passage therethrough, latches engaging said plug in said passage and a ring of com ressible material normally holding said late es in operative position releasable under shocks exerted thereon.

7. A core drill, a plug closing the core pas sage therethrough, latches engaging said plug in'said passage and a soft metal ring normally holding said latches in operative position, said latches bein adapted to indent said ring under shock and release said plug.

In testimony whereof I hereunto aflix n11; signature, this the 20th day of October, A.

' FLOYD L. SCOTT. 

